JP3402832B2 - Hot-dip metal plating equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for producing a hot-dip galvanized steel sheet, and more particularly to a so-called aerial pot for dipping a steel strip from below a molten metal holding container for plating.

[0002]

2. Description of the Related Art A method for producing a hot dip galvanized steel sheet, particularly an alloyed hot dip galvanized steel sheet, is generally as follows.
That is, after cold rolling, the surface is cleaned in a pretreatment step, a steel sheet that has been passed through a continuous annealing furnace in a non-oxidizing or reducing atmosphere is immersed from above the molten zinc bath through an antioxidant snout, The so-called sink roll arranged in the bath was used to change the direction, the molten zinc was adhered to the steel plate while being pulled up, and the excess amount of adhesion was removed outside the bath with an air knife or the like.

However, in this method, since there is a device such as a sink roll in the bath, the holding container for the molten zinc bath becomes extremely large, and the degree of freedom is small when the type of plating bath is changed, and the maintenance of the sink roll is complicated. Alternatively, there is a problem that the dross is caught between the sink roll and the steel plate to be plated, and quality defects such as surface scratches occur.

Therefore, various methods have been proposed which do not use sink rolls, but there is a so-called aerial pot method as a method capable of plating both sides of a steel sheet. As shown in FIG. 6, an opening 4 for entering a steel strip is provided at the bottom of the container 3 for holding the molten metal 2, and the steel plate 1 to be plated is passed through from below the opening 4 toward above. To do.

By the way, an important point of this aerial pot method is to prevent the molten metal 2 from leaking out from the opening 4. For this reason, for example, in JP-A-4-356, a sidewall of the opening 4 is provided. The seal plate 15 is provided, and the distance between the seal plate 15 and the steel plate 1 to be plated is 0.05 to 1 (m
m) or static pressure is applied to the opening. Also,
In Japanese Patent Laid-Open No. 63-109148, a gas nozzle for static pressure generation is provided below the steel strip introducing portion of the aerial pot, that is, below the opening 4, and static pressure is applied by the gas 17 to melt the gas from the opening. Techniques for preventing metal leakage have been disclosed. Furthermore, Japanese Patent Application No. 63-109149 proposes an aerial pot using an electromagnetic pump.

Therefore, when adopting the method of applying the static pressure to the opening in the air pot method for the molten metal plating, it is necessary to have a means for holding the static pressure by some method. In addition to this, (1) a method in which a sealing roll is provided in the steel strip introducing portion and static pressure is maintained by using a pressure seal installed in contact with this or with a very small gap (2) Steel strip to be plated It is also conceivable to use a method of holding static pressure by passing a slit slightly larger than its cross section (3) a method of holding static pressure using a labyrinth seal.

[0007]

However, in the aerial pot method, the molten metal bath is held by using static pressure or electromagnetic force. However, when actually used, the power is stopped, disturbance is generated, etc. The molten metal holding mechanism of the container was impaired and molten metal frequently flowed from the container.
Once that flow occurs, zinc will be wrapped around the deflor, and it will be picked up by the steel plate, resulting in a quality defect that requires replacement.At that time, a sealing mechanism is installed vertically below the molten metal holding container below the opening. In that case, there is a problem that the molten metal adheres to them, which further increases the downtime of the plating operation required for exchanging them and makes maintenance complicated.

For example, the seal roll 5 is added to the above-mentioned sealing mechanism.
In the method using the pressure seal 6, the molten metal 2 that has flowed down may wind around the seal roll 5, and the molten metal 2 may adhere to the pressure seal 6 between the seal roll 5 and the container 3. When this is left unattended, the molten metal 2 is picked up from the pressure seal 6 to the seal roll 5 and from the seal roll 5 to the steel plate 1 to be plated, and the steel plate 1 is also plated.
Since the spotted pattern remains on the top, not only the seal roll 5 but also the pressure seal 6 must be replaced at the same time.
This was a serious obstacle to shortening the replacement work time. Further, since the replacement of the pressure seal 6 has a connection with the removal from the container 3, it has to be replaced after waiting for the furnace temperature to drop. When the pressure seal 5 and the seal roll 6 are installed on the line, The downtime when the molten metal 2 once flows down is further increased, such as the necessity of aligning the pressure seal 6 and the seal roll 5. Further, since the temperature of the replaced pressure seal 6 has dropped, the molten metal 2 adhering thereto has solidified and is difficult to remove, which is an obstacle to maintenance.

A method using a slit or a labyrinth seal to hold the static pressure was also tried, but since the molten metal adheres to the edge of the slit or the labyrinth seal and picks up the molten metal, it is different from the case of the seal roll. Similarly,
It was necessary to replace it after waiting for the furnace temperature to cool down, and to perform maintenance, reducing downtime and hindering maintenance. Also, in the method of using a static pressure pad to maintain static pressure, the molten metal that has flowed down is scattered in the static pressure pad and adheres to walls, etc., which occasionally re-scatters and adheres to the steel plate. There is a problem that there is a pattern on the
As with the slits, the static pressure pads needed to be replaced and maintained, which also reduced downtime and hindered maintenance.

In view of such circumstances, an object of the present invention is to provide a container for a molten metal plating bath, which has a small negative effect on the plating operation even if the molten plated metal leaks.

[0011]

In order to achieve the above-mentioned object, the inventor cannot avoid leakage of molten metal to some extent. Therefore, the inventors intently consider measures against it and devise the present invention. Came to. That is, the present invention provides a static pressure holding container that covers the opening below the molten metal holding container having an opening for entering a steel strip at the bottom to prevent leakage of the molten metal and surrounds the deflor. The hot-dip metal plating apparatus is characterized in that a sealing mechanism for a steel strip entrance to the static pressure holding container is provided upstream of the deflour.

The present invention is also the hot-dip galvanizing apparatus characterized in that the sealing mechanism is any one of a seal roll, a labyrinth seal, a static pressure pad, and a slit.

[0013]

According to the present invention, the static pressure holding container is provided below the molten metal holding container having the opening for entering the steel strip at the bottom to prevent the molten metal from leaking out by covering the opening and surrounding the deflor. Since the seal mechanism for the entrance of the steel strip to the static pressure holding container is provided upstream of the deflour, the installation position of the seal mechanism can be avoided from vertically below the opening. Even when the water flows down, it is prevented from adhering to the static pressure holding seal mechanism, and it is only necessary to replace the deflor, and downtime of the plating work can be minimized. Further, there is also an effect that there is a margin in the height direction, the restriction in the height direction when installing the aerial pot is relaxed, and facility remodeling and new installation are facilitated. Further, according to the present invention, since the sealing mechanism is any one of a seal roll, a labyrinth seal, a static pressure pad and a slit, the object of the present invention can be achieved easily at low cost without providing a sealing mechanism having a special structure. Hereinafter, the content of the present invention will be specifically described in Examples.

[0014]

EXAMPLES A typical example of a molten metal plating apparatus according to the present invention is shown in FIG. As a sealing mechanism of the static pressure holding container 13, a combination of the seal roll 5 and the pressure seal 6 is used. As a result, unlike the prior art, the positions of the seal roll 5 and the pressure seal 6 are avoided from vertically below the opening 4 of the container 3, so that even if the molten metal 2 flows down, these need not be replaced. became. In this embodiment, a seal mechanism for maintaining static pressure is provided upstream of and in the immediate vicinity of the deflor 11, but this is to make the portion of the container 3 that is required to withstand pressure as small as possible. In addition, 10 is
A gas supply pipe for maintaining static pressure.

2, 3 and 4 respectively use a slit 7, a labyrinth seal 8 and a static pressure pad 9 as a sealing mechanism for the static pressure holding container 13. Also in these cases, the same effect as in the case of the combination of the seal roll 5 and the pressure seal 6 was obtained. Figure 5
In the embodiment shown in FIG. 1, a support roll 12 for preventing vibration of the steel sheet 1 to be plated and correcting the shape is provided between the deflow 11 and the opening 4 for entering the steel strip at the bottom of the molten metal holding container.
Is an example in which is provided. In this example, when the molten metal 2 leaks or flows down, it is necessary to replace and maintain not only the deflow 11 but also the support roll 12.
It is not necessary to replace or maintain the sealing mechanism for maintaining static pressure, and the benefits of the present invention can be enjoyed as in the case of FIG. Further, the effect of the present invention of FIG. 5 is more important than that of FIG. 1 in that there is a margin in the height direction.

In the embodiment shown here, a combination of the seal roll 5 and the pressure seal 6, the slit 7, the labyrinth seal 8 and the static pressure pad 9 are mentioned as the static pressure holding seal mechanism. If it is a method that avoids the vertically downward direction of the container 3 and is provided in the front stage of the deflor 11, the replacement and maintenance of the container can be reduced.
Anything will do. Further, as a method for preventing the molten metal 2 from flowing down itself, the same is true when electromagnetic force or another technique is used in addition to static pressure.

[0017]

As described above, according to the present invention, even if the molten metal leaks from the opening at the bottom of the holding container and flows down, the downtime in the plating operation is significantly reduced, and the maintenance of the apparatus is reduced. Simplified. In addition, there is a margin in the height direction, and when installing the aerial pot, the restrictions in the height direction are eased, and facility remodeling and new installation become easy.

[Brief description of drawings]

FIG. 1 shows an example in which a seal roll and a pressure seal are used in combination in a seal mechanism.

FIG. 2 shows an embodiment in which a slit is used for the seal mechanism.

FIG. 3 is an embodiment when a labyrinth seal is used for the seal mechanism.

FIG. 4 is an example in the case where a static pressure pad is used for the sealing mechanism.

FIG. 5 shows an embodiment in which a support roll is additionally provided in FIG.

FIG. 6 is a vertical sectional view showing a conventional so-called aerial pot.

[Explanation of symbols]

1 Steel strip (plated steel plate) 2 Molten metal 3 Molten metal holding container 4 openings 5 seal roll 6 Pressure seal 7 slits 8 Labyrinth seal 9 Static pressure pad 10 Gas supply pipe 11 Deflor 12 Support Roll 13 Static pressure container 14 Continuous annealing furnace 15 Seal plate

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 60-184461 (JP, A) JP 2-66144 (JP, A) JP 63-109148 (JP, A) JP 4- 356 (JP, A) Actually opened 58-22970 (JP, U) Actually opened 57-59872 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 2/00-2 / 40

Claims (5)

(57) [Claims] 1. A static pressure holding container is provided below a molten metal holding container having an opening for entering a steel strip at the bottom, which covers the opening to prevent leakage of molten metal and surrounds a deflor. A hot-dip galvanizing apparatus, wherein a sealing mechanism for a steel strip entrance to the static pressure holding container is provided upstream of the deflour. 2. The molten metal plating apparatus according to claim 1, wherein the sealing mechanism is a seal roll. 3. The molten metal plating apparatus according to claim 1, wherein the sealing mechanism is a labyrinth seal. 4. The molten metal plating apparatus according to claim 1, wherein the sealing mechanism is a static pressure pad. 5. The molten metal plating apparatus according to claim 1, wherein the sealing mechanism is a slit.